Pipes used in a variety of processes often develop undesirable deposits on the inner surface of the pipe wall. These contaminants are generally known as scale. Cleaning of these pipes is done by hydraulic propulsion of a cleaning module (called a "Pig") through the pipe. One Pig has removable tips disposed circumferentially around and extending radially outward from the body of the Pig. The hydraulic pressure forces the pig through the pipe while the tips scrape the deposits from the pipe.
Some cleaning processes randomly apply different tip types, attempting to remove the adhered deposits while preventing significant erosion of the pipe wall. For example, as disclosed in U.S. Pat. No. 5,358,573, a Pig is repeatedly cycled back and forth with each tip through a section of pipe that is "dirty". While this process may eventually remove the deposits, using a module tip that is too abrasive can result in erosion and pipe scoring. Regardless of the initial state of the pipe system, any erosion or scoring could cause either process difficulties or failures.